I have found it.
Entirely by chance when I was using the Pounce feature on Etsy.
It's the ultimate, must-have wall decal for anyone who has chronic pain:-
(And the fact that the seller has chosen a Winnie the Pooh-related shop name doesn't hurt, either!)
Shipping only offered within the US at the moment, but experience has shown that the majority of sellers respond very positively to a politely-worded request to consider shipping to the UK.